code: def test_train_test_split():
      train = load_dataset(day_index=0, object_type="DataLoader")
      test = load_dataset(day_index=30, object_type="DataLoader")
  
      assert_that(
          (len(train.dataset) + len(test.dataset)), equal_to(1706)
      )
  
file_path: deepchecks/tests/vision/datasets/test_mask.py
imports: from unittest.mock import patch
  from hamcrest import assert_that, calling, equal_to, instance_of, is_, raises
  from torch.utils.data import DataLoader
  from deepchecks.vision import VisionData
  from deepchecks.vision.datasets.detection.mask import MASK_DIR, MaskDataset, load_dataset
label_desc: Use image node_id 5 for calling a global function with example usage: test_train_test_split() without return types